How to convert LINQ query result to list and return generic List? - linq

Question

I used generic ORM list
example.
This is my table.
Person table
Guid
Name
LastName
and this is my struct class.
public struct PersonItem // database and class field names are the same
{
public Guid Guid{ get; set; }
public string Name { get; set; }
public string LastName { get; set; }
}
public struct PersonItems
{
public PersonItems()
{
Items = new List<PersonItem>();
}
public List<PersonItem> Items { get; set; }
}
I'm using such and no problem but I always have to write field's
public PersonItems GetPersons()
{
var query = (from p in _DbEntities.t_Crew
select p).ToList();
if (query != null)
{
foreach (var item in query)
{
_PersonItems.Items.Add(new PersonItem
{
Guid = item.Guid,
Name = item.Name,
LastName = item.LastName
});
}
}
return _PersonItems;
}
public PersonItems GetPersons()
{
PersonItems personItems = new PersonItems();
var query = from p in _DbEntities.t_Person
select p; >> this here query I need to convert linq query result to list
personItems = query.ToList();
return personItems ;
}
error
Cannot implicitly convert type System.Collections.Generic.List' to PersonData.PersonItems'.

Answer 1

Try this
public PersonItems GetPersons()
{
PersonItems personItems = new PersonItems();
var query = (from p in _DbEntities.t_Person
select new PersonItems
{
test = p.SomeName,
//Other Stuff
//...
}).ToList();
return query;
}

Answer 2

Comparing to the other version of your GetPersons() method, I think this line :
personItems = query.ToList();
should've been this way instead :
personItems.Items = query.ToList();
Update regarding the latest error. You can't assign list of t_Person to Item property which is of type list of PersonItem. Hence, your query need to be adjusted to return list of PersonItem :
var query = from p in _DbEntities.t_Person
select new PersonItem
{
Guid = p.Guid,
Name = p.Name,
LastName = p.LastName
};
or other option is to change definition of Item property to list of t_Person :
public List<t_Person> Items { get; set; }

Answer 3

Cannot implicitly convert type System.Collections.Generic.List' to PersonData.PersonItems'
Above error says that you are trying to convert generic list to PersonItems.
So at this line, query.ToList() code returns List<PersonItem> not the PersonItems
var query = from p in _DbEntities.t_Person
select p; >> this here query I need to convert linq query result to list
personItems = query.ToList();
return personItems ;
So thats the reason above line of code fails.

Answer 4

What about this?
Change .ctor of PersonItems:
public struct PersonItems
{
public PersonItems(List<PersonItem> items)
{
Items = items;
}
public List<PersonItem> Items { get; set; }
}
And then method GetPersons():
public PersonItems GetPersons()
{
return new PersonItems(_DbEntities.t_Person.ToList());
}